CADULUS-POLYSCHIDES. 151 



Length 8'6 mill., diam. at aperture 0'85 x 1*0, at largest T12 x 

 1-22, at apex 0'65 x O7 mill. 



San Diego, California, 10 fms. (Henry Hemphill, in Acad. coll.) ; 

 San Pedro (Smithsonian Institution). 



Siphonodentdlium 4'fi ssa ^ um CARPENTER, mss. label in Smithso- 

 nian Institution collection. 



Extremely similar to C. quadridentatus of the Antillean fauna ; 

 but in the Californian species the aperture is somewhat less oblique, 

 the apical slits are shorter, the teeth all more conspicuously bevelled 

 and the tooth on the convex side less elongated. These differences 

 we would hardly hold of specific value were it not for the geographic 

 separation of the two species ; still they seem constant so far as our 

 material goes. 



The figures and measurements are from a San Diego specimen in 

 coll. Acad. Nat. Sci. Phila. The Smithsonian Institution example, 

 which bore the above name, is somewhat smaller, not fully adult, 

 length 7-2 mill. 



C. TETRODON Pilsbry & Sharp, n. sp. PI. 29, figs. 14, 15, 16, 17, 18. 



Shell small, slender, slightly arcuate,translucent and slightly bluish 

 with a white line or band near the apex ; but little inflated, the great- 

 est girth at the anterior two-fifths of the length, from this point quite 

 perceptibly tapering toward each end. Outline of concave side a trifle 

 convex in the region of inflation ; greatest diameter contained about 

 5? times in the length of the shell. Surface glossy, without percep- 

 tible growth striae. Aperture oblique, nearly circular, the blunt 

 peristome a little contracted along the convex margin. Anal orifice 

 rounded-oval, slit into four blunt lobes or teeth, one on the convex 

 side slightly longer, rounded ; one on concave side truncated, the 

 two lateral lobes slightly narrower; each more or less bevelled to 

 an edge. 



Length 5'6 mill., diam. at aperture 0'57 x 0*6, at greatest inflation 

 0-95 x 1-0, at apex 0'35 x (M3 mill. 



Length 5 mill., antero-posterior diam. at aperture 0*6, at greatest 

 0'88, at apex 0'4 mill. 



Five miles of Cape Florida, in 8 fms. (Dr. W. H. Rush, U. S. 

 N.). 



This species is smaller than C. tetrasehistus, quadridentatus and 

 incisus, and is decidedly more swollen and fusiform, the difference 

 in this respect being particularly conspicuous. In general outline 



